Technical Field
Exemplary embodiments of the invention relate to a lamp unit to be mounted on a vehicle.
Related Art
A unit having a light source, a projection lens and a shade has been known as such a lamp unit. The projection lens is disposed so that at least a part of light emitted from the light source passes through the projection lens. The shade is disposed in rear of the projection lens so as to block a part of the light emitted from the light source. The light passing through the projection lens forms a light distribution pattern that illuminates an area ahead of the lamp unit. On this occasion, an edge of the shade is projected ahead of the projection lens as a peripheral edge of the light distribution pattern. A low beam pattern that illuminates an area ahead of the vehicle by a short distance so as to cause no glare to vehicles running ahead is exemplified as one example of the light distribution pattern. A cutoff line that forms an upper edge of the low beam pattern is exemplified as one example of the peripheral edge of the light distribution pattern.
There is a demand to blur the cutoff line in order to improve forward visibility and suppress a sense of discomfort felt by a driver. To meet this demand, there has been known a configuration in which a light scattering surface is formed on a surface of a projection lens so that light projecting an edge of a shade passes through the light scattering surface (for example, see JP 2007-265864 A (corresponding to U.S. Pat. No. 7,736,036 B2)).